Electric shavers usually have one or more cutter elements driven by an electric drive unit in an oscillating manner where the cutter elements reciprocate under a shearfoil, wherein such cutter elements or undercutters may have an elongated shape and may reciprocate along their longitudinal axis. Other types of electric shavers use rotatory cutter elements which may be driven in an oscillating or a continuous manner. Said electric drive unit may include an electric motor or an electric-type linear motor, wherein the drive unit may include a drive train having elements such as an elongated drive transmitter for transmitting the driving motion of the motor to the cutter element, wherein the motor may be received within the handle portion of the shaver or in the alternative, in the shaver head thereof.
Such drive units are sometimes operable in different operation modes, wherein for example the cutter speed or oscillation frequency may be varied to increase shaving efficiency in a fast mode or highspeed mode, whereas power consumption may be reduced in a slow mode or low speed mode. Depending on the fittings of the shaver, other operation modes may be offered and may include a long-hair cutting mode in which the drive unit, in addition to or in the alternative to driving the at least one cutter unit, may drive a long hair cutter, or a fluid application mode in which a lubricating applicator such as a spray nozzle may be activated, or a ventilating mode in which a ventilator may be driven by the drive unit to generate airflow to achieve cooling or cleaning.
So as to give a user the option to choose between those different operation modes, the shaver may be provided with a mode input element such as a touch button, a toggle switch or a gesture sensor to allow the user to input a respective mode command switching the shaver's drive unit and/or a control unit into the desired operation mode. For example, document US 2015/0246454 A shows an electric shaver operable in more than one operating mode, wherein a mode input element is provided for switching the driving unit into different operation modes. Sometimes switching between different operation modes may be effected automatically, for example the aforementioned low speed mode may be chosen automatically when the battery charging level becomes low.
In order to give the user feedback which operation mode has been selected, such shavers may have a display device for displaying information about such operation mode. For example, the selected cutter speed may be indicated, or the activation of functional accessories such as the aforementioned fluid applicator or airflow generator may be displayed.
In addition or in the alternative to displaying such information on the operation mode, other information may be displayed by such display devices. For example, the charging status of a battery or accumulator of the shaver may be indicated, or the shaving time may be displayed, wherein such additional information also may be displayed when the shaver or the drive unit thereof is inactive. For example, it has been suggested to extend the activity of the display to a period of some seconds after switching off the shaver so that, for example, the battery charge level is indicated for some seconds after switching off the shaver and thereafter, fading out to the idle mode in which no information is displayed. Document WO 98/25736 A suggests to display certain shaver information on the shaver's charging/cleaning station which is provided with a display for displaying such data and communicates with the shaver for receiving user data from the shaver. It also has been suggested that the sleeping display can be waked up when the power button of the shaver is briefly touched.
Sometimes such shavers may be provided with additional personal care tools such as a skin treatment unit or a long-hair cutter unit or a beard trimmer. Such skin treatment units may comprise, for example, tooling elements such as a peeling tool, a massage brush or vibration elements for enhancing blood circulation. Such skincare tools can be fixedly or releasably attached to the head portion of the device. For example, document WO 2009/027928 A discloses a personal care appliance having a head provided with coupling means for coupling different types of tools with the drive transmitter, such tools including a vibrating safety razor, a hair trimming device and a comb attachment.